Moderate senators from both parties are working behind the scenes on a compromise as a battle plays out on the Senate floor on whether President Bush's judicial nominees should all be given a straight confirmation vote in the chamber.

Although lawmakers involved in the talks say progress is being made, they're unsure a deal will necessarily be made on Wednesday.

"I would hope so, [but] predicting time is problematic," said Sen. Ben Nelson, D-Neb. "The goal is to get it done as soon as possible."

After meeting for over an hour in Sen. John Warner's office, senators who are interested in drafting a compromise that would avoid triggering the so-called "nuclear option" expressed optimism.

"No news except to say that we're making some progress but we have no conclusion yet," said Sen. John McCain, R-Ariz.

Added Nelson: "We're just going to keep getting together -- we wouldn't continue to do it if we didn't have some expectation of achieving an agreement. It's a challenging effort -- it's very, very dynamic and we're going to continue to pursue and push ahead."

Nelson said those involved are reforming and changing a "single draft" compromise that may provide floor votes for most but not all of blocked nominees.

"We're certainly not done -- you know, we're not there yet and we may never get there -- but you know, I think we're getting closer," added Sen. Mike DeWine, R-Ohio, after another meeting.

The discussions took place as Senate Republicans began debate on the judicial nomination of Priscilla Owen to the 5th Circuit Court of Appeals on Wednesday. Republicans argue that removing the procedural barrier of a filibuster -- otherwise known as the "nuclear option" -- is the only way to get a vote on stalled judicial nominees.

But Democrats blasted any efforts to abolish filibusters as an abuse of power by a few lawmakers in the clutches of radical conservative groups. They are threatening to grind to a halt any work in the chamber if Republicans employ the nuclear option.

Nuclear Power Grab?

Sixty Senate votes are needed to overcome a filibuster, the endless debate aimed at preventing a vote. Only 51 votes are needed to approve a candidate if he or she is given a regular vote.

Senate Majority Leader Bill Frist of Tennessee said Wednesday a minority of senators is preventing the chamber from getting on with pressing business.

"They will obstruct the Senate's business, they will obstruct America's business," Frist said, including work from being done on items such as energy legislation, medical malpractice reform and a simpler tax code.

"A minority of senators will hold America back just because a majority of senators, a majority of people in this body, want to do what most Americans ... expect us to do -- and that is to vote," he said. "We should vote up or down on judicial nominees."

He said President Bush has been "saddled" with the lowest confirmation rate of appeals court nominees of any modern president.

"Senators are simply not doing their job," Frist said, noting 46 vacancies on the federal bench, 17 of which are in the appeals courts. "This is disgraceful ... don't leave [the nominees] hanging ... don't leave the courts hanging, don't leave our country hanging."

Frist added: "We will choose the Constitution over obstruction … we will choose votes over vacillation and when we do, the Senate will be the better for it."

But Senate Democratic Leader Harry Reid of Nevada said the thought of eliminating the filibuster is just another sign of the "arrogance of power of this Republican administration."

"It's not enough that they come to the people's body and say 'let's take our chances by a fair ballgame.' They're going to change the rules in the middle of the ballgame," Reid said. "This administration is unwilling to play by the rules ... the filibuster is a critical tool in keeping the majority in check."

Earlier Wednesday, Sens. Ted Kennedy of Massachusetts and Pat Leahy of Vermont argued in favor of letting other less controversial nominees get a vote before Owen. Reid also requested a "senators only" meeting to discuss options other than going nuclear, stressing that it wasn't his party that was interested in "breaking the rules."

But Frist said such sideline discussions were just more "attempts to delay, more attempts to sidetrack" the process.

"All we want is a vote, an up-or-down vote," on Owen, he added, to decide whether or not that nominee is "out of the mainstream," as Democrats have suggested.

Sen. Arlen Specter, the chairman of the Senate Judiciary Committee, who still falls in the "undecided" category of Republicans considering how to vote on the nuclear option if no compromise is reached, warned colleagues on Wednesday about the implications of voting to change the filibuster rule and said the issue has gotten out of control.

"To achieve compromise, senators must do so without being influenced by the far right and left," the Pennsylvania lawmaker said. "I continue to be highly offended by ads seeking to influence my own vote ... they are counter-productive ... [they're] ineffectual and certainly insulting."

Specter added that nominees would be confirmed "if the straight jacket of party loyalty were removed."

Compromise in the Works?

On Monday, Reid ended negotiations with Frist to avoid the nuclear option. Nelson and McCain, along with six Democrats and six Republicans have been working on a possible compromise that would preserve the use of the filibuster and guarantee confirmation votes on up to five of the seven blocked Bush judicial nominees.

"Members of both sides of the aisle recognize from time to time that to get something, you have to give something," Nelson told FOX News Wednesday morning.

"We're still working on the language but I'm not sure that means a withdrawal" of any nominees, Nelson continued, adding that any compromise would include not only a process to follow regarding the seven or eight pending nominations but also with future nominations, as well.

Top Nelson aides had earlier told FOX News that Nelson and five Democrats are willing to allow floor votes on Owen and Brown, but only if Republicans agree to keep the filibuster -- albeit sparingly -- and abandon some of the president's lesser-known judicial nominees.

Sen. Orrin Hatch, a Republican on the Senate Judiciary Committee, credited Nelson for standing up and working with Republicans on a compromise.

"He's been sort of a voice in the wilderness over on the Democrats' side," Hatch told FOX News.

The senators involved in the negotiations are Republicans McCain, DeWine, John Warner of Virginia, Olympia Snow of Maine, Lindsey Graham of South Carolina, Susan Collins of Maine and Lincoln Chafee of Rhode Island. Democrats Nelson, Mark Pryor of Arkansas, Ken Salazar of Colorado, Joseph Lieberman of Connecticut, and potentially Robert Byrd of West Virginia and Mary Landrieu of Louisiana -- depending on the language on the nuclear pledge and on the judges included -- are also involved in the talks.

A GOP source close to negotiations told FOX News Wednesday afternoon that the situation is "incredibly fluid" and that the greatest challenge is mapping out language on the nuclear pledge and on which judge Democrats would have to agree to confirm. Reid has said he wants the nuclear option off the table altogether.

The letter being circulated Wednesday means very little until all 12 senators agree to it contents. On Wednesday, Democrats involved in the talks agreed to allow confirmation votes on Owen and Brown if that would help seal a deal.

To use the filibuster, Reid would need 40 votes out of the 44 Democrats and one independent who votes with Democrats. If six Democrats defect, Reid would have 39 votes and could not filibuster.

To invoke the nuclear option and end judicial filibusters, Frist would need 51 votes (including Vice President Dick Cheney, who would break a tie) of the 55 Republicans in the Senate. If six defect, Frist can't change the rules.

Sources on both sides of the aisle said they don't expect anything to gel on Wednesday but that could happen Thursday or next week.

Bush: Senate Has Duty to Vote

The GOP leadership likely will early next week call for a vote to end debate on Owen's nomination. If they are unable to end debate, they will vote to abolish filibusters on judicial nominees. That vote requires a simple majority to succeed.

Owen and Janice Rogers Brown, a California Supreme Court justice nominated to the Circuit Court of Appeals for the District of Columbia, appeared on Capitol Hill Tuesday and visiting the White House and Bush.

"I have a duty to nominate well-qualified men and women to the federal judiciary. I have done just that, and I will continue to do so," Bush said during comments at a Republican National Committee gala in Washington on Tuesday night.

"The Senate also has a duty to promptly consider each of these nominees on the Senate floor, discuss and debate their qualifications, and then give them the up or down vote they deserve."

Sen. Charles Schumer, D-N.Y., said on the Senate floor Wednesday that Bush has made no efforts to consult lawmakers on his judicial picks -- many of whom are too conservative for Democrats' liking -- and that's a big reason his nominees are being blocked. Schumer also vowed that his party would block progress on any issue if the nuclear option is approved.

"He has reaped what he has sown -- no consultation, no discussions and nominees who tend to be way over to the extreme," Schumer said. "No president has taken so little care in the proposing of judges."

Schumer urged lawmakers to resist the pressure and "avoid undue influence" of minority groups that he labeled "hard, hard right extremists" that fall in the far right of the ideological spectrum who want to "cheat" to get their way. He said the country's founding fathers didn't intend mean for lawmakers to walk "lockstep like lemmings" behind the president on every judicial nominee.

"If there was ever a time where the power grab has been so harsh, so real and so unyielding, it seems to be now," he added.

FOX News' Major Garrett, Julie Asher and Molly Hooper contributed to this report.